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                                <h2 id="&#x8BA1;&#x6570;&#x5668;&#x5E94;&#x7528;&#x793A;&#x4F8B;">&#x8BA1;&#x6570;&#x5668;&#x5E94;&#x7528;&#x793A;&#x4F8B;</h2>
<p>&#x7528;Android Studio&#x548C;VS Code&#x521B;&#x5EFA;&#x7684;Flutter&#x5E94;&#x7528;&#x6A21;&#x677F;&#x662F;&#x4E00;&#x4E2A;&#x7B80;&#x5355;&#x7684;&#x8BA1;&#x6570;&#x5668;&#x793A;&#x4F8B;&#xFF0C;&#x672C;&#x8282;&#x5148;&#x4ED4;&#x7EC6;&#x8BB2;&#x89E3;&#x4E00;&#x4E0B;&#x8FD9;&#x4E2A;&#x8BA1;&#x6570;&#x5668;Demo&#x7684;&#x6E90;&#x7801;&#xFF0C;&#x8BA9;&#x8BFB;&#x8005;&#x5BF9;Flutter&#x5E94;&#x7528;&#x7A0B;&#x5E8F;&#x7ED3;&#x6784;&#x6709;&#x4E2A;&#x57FA;&#x672C;&#x4E86;&#x89E3;&#xFF0C;&#x5728;&#x968F;&#x540E;&#x5C0F;&#x8282;&#x4E2D;&#xFF0C;&#x5C06;&#x4F1A;&#x57FA;&#x4E8E;&#x6B64;&#x793A;&#x4F8B;&#xFF0C;&#x4E00;&#x6B65;&#x4E00;&#x6B65;&#x6DFB;&#x52A0;&#x4E00;&#x4E9B;&#x65B0;&#x7684;&#x529F;&#x80FD;&#x6765;&#x4ECB;&#x7ECD;Flutter&#x5E94;&#x7528;&#x7684;&#x5176;&#x5B83;&#x6982;&#x5FF5;&#x4E0E;&#x6280;&#x672F;&#x3002;&#x5BF9;&#x4E8E;&#x63A5;&#x4E0B;&#x6765;&#x7684;&#x793A;&#x4F8B;&#xFF0C;&#x5E0C;&#x671B;&#x8BFB;&#x8005;&#x53EF;&#x4EE5;&#x8DDF;&#x7740;&#x7B14;&#x8005;&#x5B9E;&#x9645;&#x52A8;&#x624B;&#x6765;&#x5199;&#x4E00;&#x4E0B;&#xFF0C;&#x8FD9;&#x6837;&#x4E0D;&#x4EC5;&#x53EF;&#x4EE5;&#x52A0;&#x6DF1;&#x5370;&#x8C61;&#xFF0C;&#x800C;&#x4E14;&#x4E5F;&#x4F1A;&#x5BF9;&#x4ECB;&#x7ECD;&#x7684;&#x6982;&#x5FF5;&#x4E0E;&#x6280;&#x672F;&#x6709;&#x4E00;&#x4E2A;&#x771F;&#x5207;&#x7684;&#x4F53;&#x4F1A;&#x3002;&#x5982;&#x679C;&#x4F60;&#x8FD8;&#x4E0D;&#x662F;&#x5F88;&#x719F;&#x6089;Dart&#x6216;&#x8005;&#x6CA1;&#x6709;&#x79FB;&#x52A8;&#x5F00;&#x53D1;&#x7ECF;&#x9A8C;&#xFF0C;&#x4E0D;&#x7528;&#x62C5;&#x5FC3;&#xFF0C;&#x53EA;&#x8981;&#x4F60;&#x719F;&#x6089;&#x9762;&#x5411;&#x5BF9;&#x8C61;&#x548C;&#x57FA;&#x672C;&#x7F16;&#x7A0B;&#x6982;&#x5FF5;&#xFF08;&#x5982;&#x53D8;&#x91CF;&#x3001;&#x5FAA;&#x73AF;&#x548C;&#x6761;&#x4EF6;&#x63A7;&#x5236;&#xFF09;&#xFF0C;&#x5219;&#x53EF;&#x4EE5;&#x5B8C;&#x6210;&#x672C;&#x793A;&#x4F8B;&#x3002;</p>
<p>&#x901A;&#x8FC7;Android Studio&#x548C;VS Code&#x6839;&#x636E;&#x524D;&#x9762;&#x201C;&#x7F16;&#x8F91;&#x5668;&#x914D;&#x7F6E;&#x4E0E;&#x4F7F;&#x7528;&#x201D;&#x4E00;&#x7AE0;&#x4E2D;&#x4ECB;&#x7ECD;&#x7684;&#x521B;&#x5EFA;Flutter&#x5DE5;&#x7A0B;&#x7684;&#x65B9;&#x6CD5;&#x521B;&#x5EFA;&#x4E00;&#x4E2A;&#x65B0;&#x7684;Flutter&#x5DE5;&#x7A0B;&#xFF0C;&#x547D;&#x540D;&#x4E3A;&quot;first_flutter_app&quot;&#x3002;&#x521B;&#x5EFA;&#x597D;&#x540E;&#xFF0C;&#x5C31;&#x4F1A;&#x5F97;&#x5230;&#x4E00;&#x4E2A;&#x8BA1;&#x6570;&#x5668;&#x5E94;&#x7528;&#x7684;Demo&#x3002;</p>
<blockquote>
<p>&#x6CE8;&#x610F;&#xFF0C;&#x9ED8;&#x8BA4;Demo&#x793A;&#x4F8B;&#x53EF;&#x80FD;&#x968F;&#x7740;&#x7F16;&#x8F91;&#x5668;Flutter&#x63D2;&#x4EF6;&#x7248;&#x672C;&#x53D8;&#x5316;&#x800C;&#x53D8;&#x5316;&#xFF0C;&#x672C;&#x4F8B;&#x4E2D;&#x4F1A;&#x4ECB;&#x7ECD;&#x8BA1;&#x6570;&#x5668;&#x793A;&#x4F8B;&#x7684;&#x5168;&#x90E8;&#x4EE3;&#x7801;&#xFF0C;&#x6240;&#x4EE5;&#x4E0D;&#x4F1A;&#x5BF9;&#x672C;&#x793A;&#x4F8B;&#x4EA7;&#x751F;&#x5F71;&#x54CD;&#x3002;</p>
</blockquote>
<p>&#x6211;&#x4EEC;&#x5148;&#x8FD0;&#x884C;&#x6B64;&#x793A;&#x4F8B;&#xFF0C;&#x6548;&#x679C;&#x56FE;&#x5982;&#x4E0B;&#xFF1A;</p>
<p><img src="https://cdn.jsdelivr.net/gh/flutterchina/flutter-in-action@1.0/docs/imgs/flutter_starter_app.png" alt="flutter_starter_app"></p>
<p>&#x8BE5;&#x8BA1;&#x6570;&#x5668;&#x793A;&#x4F8B;&#x4E2D;&#xFF0C;&#x6BCF;&#x70B9;&#x51FB;&#x4E00;&#x6B21;&#x53F3;&#x4E0B;&#x89D2;&#x5E26;&#x201C;&#x2795;&#x201D;&#x53F7;&#x7684;&#x60AC;&#x6D6E;&#x6309;&#x94AE;&#xFF0C;&#x5C4F;&#x5E55;&#x4E2D;&#x592E;&#x7684;&#x6570;&#x5B57;&#x5C31;&#x4F1A;&#x52A0;1&#x3002;</p>
<p>&#x5728;&#x8FD9;&#x4E2A;&#x793A;&#x4F8B;&#x4E2D;&#xFF0C;&#x4E3B;&#x8981;Dart&#x4EE3;&#x7801;&#x662F;&#x5728; <strong>lib/main.dart</strong> &#x6587;&#x4EF6;&#x4E2D;&#xFF0C;&#x4E0B;&#x9762;&#x6211;&#x4EEC;&#x770B;&#x770B;&#x8BE5;&#x793A;&#x4F8B;&#x7684;&#x6E90;&#x7801;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">import</span> <span class="token string">&apos;package:flutter/material.dart&apos;</span><span class="token punctuation">;</span>

<span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">&gt;</span> <span class="token function">runApp</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">MyApp</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token keyword">class</span> <span class="token class-name">MyApp</span> <span class="token keyword">extends</span> <span class="token class-name">StatelessWidget</span> <span class="token punctuation">{</span>
  <span class="token metadata symbol">@override</span>
  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">MaterialApp</span><span class="token punctuation">(</span>
      title<span class="token punctuation">:</span> <span class="token string">&apos;Flutter Demo&apos;</span><span class="token punctuation">,</span>
      theme<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">ThemeData</span><span class="token punctuation">(</span>
        primarySwatch<span class="token punctuation">:</span> Colors<span class="token punctuation">.</span>blue<span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
      home<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">MyHomePage</span><span class="token punctuation">(</span>title<span class="token punctuation">:</span> <span class="token string">&apos;Flutter Demo Home Page&apos;</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">MyHomePage</span> <span class="token keyword">extends</span> <span class="token class-name">StatefulWidget</span> <span class="token punctuation">{</span>
  <span class="token function">MyHomePage</span><span class="token punctuation">(</span><span class="token punctuation">{</span>Key key<span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>title<span class="token punctuation">}</span><span class="token punctuation">)</span> <span class="token punctuation">:</span> <span class="token keyword">super</span><span class="token punctuation">(</span>key<span class="token punctuation">:</span> key<span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token keyword">final</span> String title<span class="token punctuation">;</span>

  <span class="token metadata symbol">@override</span>
  _MyHomePageState <span class="token function">createState</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">&gt;</span> <span class="token keyword">new</span> <span class="token class-name">_MyHomePageState</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">_MyHomePageState</span> <span class="token keyword">extends</span> <span class="token class-name">State</span><span class="token operator">&lt;</span>MyHomePage<span class="token operator">&gt;</span> <span class="token punctuation">{</span>
  int _counter <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span>

  <span class="token keyword">void</span> <span class="token function">_incrementCounter</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      _counter<span class="token operator">++</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>

  <span class="token metadata symbol">@override</span>
  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">Scaffold</span><span class="token punctuation">(</span>
      appBar<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">AppBar</span><span class="token punctuation">(</span>
        title<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Text</span><span class="token punctuation">(</span>widget<span class="token punctuation">.</span>title<span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
      body<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Center</span><span class="token punctuation">(</span>
        child<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Column</span><span class="token punctuation">(</span>
          mainAxisAlignment<span class="token punctuation">:</span> MainAxisAlignment<span class="token punctuation">.</span>center<span class="token punctuation">,</span>
          children<span class="token punctuation">:</span> <span class="token operator">&lt;</span>Widget<span class="token operator">&gt;</span><span class="token punctuation">[</span>
            <span class="token keyword">new</span> <span class="token class-name">Text</span><span class="token punctuation">(</span>
              <span class="token string">&apos;You have pushed the button this many times:&apos;</span><span class="token punctuation">,</span>
            <span class="token punctuation">)</span><span class="token punctuation">,</span>
            <span class="token keyword">new</span> <span class="token class-name">Text</span><span class="token punctuation">(</span>
              <span class="token string">&apos;$_counter&apos;</span><span class="token punctuation">,</span>
              style<span class="token punctuation">:</span> Theme<span class="token punctuation">.</span><span class="token function">of</span><span class="token punctuation">(</span>context<span class="token punctuation">)</span><span class="token punctuation">.</span>textTheme<span class="token punctuation">.</span>display1<span class="token punctuation">,</span>
            <span class="token punctuation">)</span><span class="token punctuation">,</span>
          <span class="token punctuation">]</span><span class="token punctuation">,</span>
        <span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
      floatingActionButton<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">FloatingActionButton</span><span class="token punctuation">(</span>
        onPressed<span class="token punctuation">:</span> _incrementCounter<span class="token punctuation">,</span>
        tooltip<span class="token punctuation">:</span> <span class="token string">&apos;Increment&apos;</span><span class="token punctuation">,</span>
        child<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Icon</span><span class="token punctuation">(</span>Icons<span class="token punctuation">.</span>add<span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token comment">// This trailing comma makes auto-formatting nicer for build methods.</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<h3 id="&#x5206;&#x6790;">&#x5206;&#x6790;</h3>
<ol>
<li><p>&#x5BFC;&#x5165;&#x5305;&#x3002;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">import</span> <span class="token string">&apos;package:flutter/material.dart&apos;</span><span class="token punctuation">;</span>
</code></pre>
<p>&#x6B64;&#x884C;&#x4EE3;&#x7801;&#x4F5C;&#x7528;&#x662F;&#x5BFC;&#x5165;&#x4E86;Material UI&#x7EC4;&#x4EF6;&#x5E93;&#x3002;<a href="https://material.io/guidelines/" target="_blank">Material</a>&#x662F;&#x4E00;&#x79CD;&#x6807;&#x51C6;&#x7684;&#x79FB;&#x52A8;&#x7AEF;&#x548C;web&#x7AEF;&#x7684;&#x89C6;&#x89C9;&#x8BBE;&#x8BA1;&#x8BED;&#x8A00;&#xFF0C; Flutter&#x9ED8;&#x8BA4;&#x63D0;&#x4F9B;&#x4E86;&#x4E00;&#x5957;&#x4E30;&#x5BCC;&#x7684;Material&#x98CE;&#x683C;&#x7684;UI&#x7EC4;&#x4EF6;&#x3002;</p>
</li>
<li><p>&#x5E94;&#x7528;&#x5165;&#x53E3;&#x3002;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">&gt;</span> <span class="token function">runApp</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">MyApp</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre>
<ul>
<li>&#x4E0E;C/C++&#x3001;Java&#x7C7B;&#x4F3C;&#xFF0C;Flutter &#x5E94;&#x7528;&#x4E2D;<code>main</code>&#x51FD;&#x6570;&#x4E3A;&#x5E94;&#x7528;&#x7A0B;&#x5E8F;&#x7684;&#x5165;&#x53E3;&#xFF0C;main&#x51FD;&#x6570;&#x4E2D;&#x8C03;&#x7528;&#x4E86;&#xFF0C;<code>runApp</code> &#x65B9;&#x6CD5;&#xFF0C;&#x5B83;&#x7684;&#x529F;&#x80FD;&#x662F;&#x542F;&#x52A8;Flutter&#x5E94;&#x7528;&#xFF0C;&#x5B83;&#x63A5;&#x53D7;&#x4E00;&#x4E2A;<code>Widget</code>&#x53C2;&#x6570;&#xFF0C;&#x5728;&#x672C;&#x793A;&#x4F8B;&#x4E2D;&#x5B83;&#x662F;<code>MyApp</code>&#x7C7B;&#x7684;&#x4E00;&#x4E2A;&#x5B9E;&#x4F8B;&#xFF0C;&#x8BE5;&#x53C2;&#x6570;&#x4EE3;&#x8868;Flutter&#x5E94;&#x7528;&#x3002;</li>
<li>main&#x51FD;&#x6570;&#x4F7F;&#x7528;&#x4E86;(<code>=&gt;</code>)&#x7B26;&#x53F7;&#xFF0C;&#x8FD9;&#x662F;Dart&#x4E2D;&#x5355;&#x884C;&#x51FD;&#x6570;&#x6216;&#x65B9;&#x6CD5;&#x7684;&#x7B80;&#x5199;&#x3002;</li>
</ul>
</li>
<li><p>&#x5E94;&#x7528;&#x7ED3;&#x6784;&#x3002;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">class</span> <span class="token class-name">MyApp</span> <span class="token keyword">extends</span> <span class="token class-name">StatelessWidget</span> <span class="token punctuation">{</span>
  <span class="token metadata symbol">@override</span>
  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">MaterialApp</span><span class="token punctuation">(</span>
      <span class="token comment">//&#x5E94;&#x7528;&#x540D;&#x79F0;  </span>
      title<span class="token punctuation">:</span> <span class="token string">&apos;Flutter Demo&apos;</span><span class="token punctuation">,</span> 
      theme<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">ThemeData</span><span class="token punctuation">(</span>
        <span class="token comment">//&#x84DD;&#x8272;&#x4E3B;&#x9898;  </span>
        primarySwatch<span class="token punctuation">:</span> Colors<span class="token punctuation">.</span>blue<span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token comment">//&#x5E94;&#x7528;&#x9996;&#x9875;&#x8DEF;&#x7531;  </span>
      home<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">MyHomePage</span><span class="token punctuation">(</span>title<span class="token punctuation">:</span> <span class="token string">&apos;Flutter Demo Home Page&apos;</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<ul>
<li><code>MyApp</code>&#x7C7B;&#x4EE3;&#x8868;Flutter&#x5E94;&#x7528;&#xFF0C;&#x5B83;&#x7EE7;&#x627F;&#x4E86; <code>StatelessWidget</code>&#x7C7B;&#xFF0C;&#x8FD9;&#x4E5F;&#x5C31;&#x610F;&#x5473;&#x7740;&#x5E94;&#x7528;&#x672C;&#x8EAB;&#x4E5F;&#x662F;&#x4E00;&#x4E2A;widget&#x3002;</li>
<li>&#x5728;Flutter&#x4E2D;&#xFF0C;&#x5927;&#x591A;&#x6570;&#x4E1C;&#x897F;&#x90FD;&#x662F;widget&#xFF0C;&#x5305;&#x62EC;&#x5BF9;&#x9F50;(alignment)&#x3001;&#x586B;&#x5145;(padding)&#x548C;&#x5E03;&#x5C40;(layout)&#x3002;</li>
<li>Flutter&#x5728;&#x6784;&#x5EFA;&#x9875;&#x9762;&#x65F6;&#xFF0C;&#x4F1A;&#x8C03;&#x7528;&#x7EC4;&#x4EF6;&#x7684;<code>build</code>&#x65B9;&#x6CD5;&#xFF0C;widget&#x7684;&#x4E3B;&#x8981;&#x5DE5;&#x4F5C;&#x662F;&#x63D0;&#x4F9B;&#x4E00;&#x4E2A;build()&#x65B9;&#x6CD5;&#x6765;&#x63CF;&#x8FF0;&#x5982;&#x4F55;&#x6784;&#x5EFA;UI&#x754C;&#x9762;&#xFF08;&#x901A;&#x5E38;&#x662F;&#x901A;&#x8FC7;&#x7EC4;&#x5408;&#x3001;&#x62FC;&#x88C5;&#x5176;&#x5B83;&#x57FA;&#x7840;widget&#xFF09;&#x3002;</li>
<li><code>MaterialApp</code> &#x662F;Material&#x5E93;&#x4E2D;&#x63D0;&#x4F9B;&#x7684;Flutter APP&#x6846;&#x67B6;&#xFF0C;&#x901A;&#x8FC7;&#x5B83;&#x53EF;&#x4EE5;&#x8BBE;&#x7F6E;&#x5E94;&#x7528;&#x7684;&#x540D;&#x79F0;&#x3001;&#x4E3B;&#x9898;&#x3001;&#x8BED;&#x8A00;&#x3001;&#x9996;&#x9875;&#x53CA;&#x8DEF;&#x7531;&#x5217;&#x8868;&#x7B49;&#x3002;<code>MaterialApp</code>&#x4E5F;&#x662F;&#x4E00;&#x4E2A;widget&#x3002;</li>
<li><code>Scaffold</code> &#x662F;Material&#x5E93;&#x4E2D;&#x63D0;&#x4F9B;&#x7684;&#x9875;&#x9762;&#x811A;&#x624B;&#x67B6;&#xFF0C;&#x5B83;&#x5305;&#x542B;&#x5BFC;&#x822A;&#x680F;&#x548C;Body&#x4EE5;&#x53CA;FloatingActionButton&#xFF08;&#x5982;&#x679C;&#x9700;&#x8981;&#x7684;&#x8BDD;&#xFF09;&#x3002; &#x672C;&#x4E66;&#x540E;&#x9762;&#x793A;&#x4F8B;&#x4E2D;&#xFF0C;&#x8DEF;&#x7531;&#x9ED8;&#x8BA4;&#x90FD;&#x662F;&#x901A;&#x8FC7;<code>Scaffold</code>&#x521B;&#x5EFA;&#x3002;</li>
<li><code>home</code> &#x4E3A;Flutter&#x5E94;&#x7528;&#x7684;&#x9996;&#x9875;&#xFF0C;&#x5B83;&#x4E5F;&#x662F;&#x4E00;&#x4E2A;widget&#x3002;</li>
</ul>
</li>
<li><p>&#x9996;&#x9875;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">class</span> <span class="token class-name">MyHomePage</span> <span class="token keyword">extends</span> <span class="token class-name">StatefulWidget</span> <span class="token punctuation">{</span>
  <span class="token function">MyHomePage</span><span class="token punctuation">(</span><span class="token punctuation">{</span>Key key<span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>title<span class="token punctuation">}</span><span class="token punctuation">)</span> <span class="token punctuation">:</span> <span class="token keyword">super</span><span class="token punctuation">(</span>key<span class="token punctuation">:</span> key<span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token keyword">final</span> String title<span class="token punctuation">;</span>
  <span class="token metadata symbol">@override</span>
  _MyHomePageState <span class="token function">createState</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">&gt;</span> <span class="token keyword">new</span> <span class="token class-name">_MyHomePageState</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">_MyHomePageState</span> <span class="token keyword">extends</span> <span class="token class-name">State</span><span class="token operator">&lt;</span>MyHomePage<span class="token operator">&gt;</span> <span class="token punctuation">{</span>
 <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token punctuation">}</span>
</code></pre>
</li>
</ol>
<p>   <code>MyHomePage</code> &#x662F;&#x5E94;&#x7528;&#x7684;&#x9996;&#x9875;&#xFF0C;&#x5B83;&#x7EE7;&#x627F;&#x81EA;<code>StatefulWidget</code>&#x7C7B;&#xFF0C;&#x8868;&#x793A;&#x5B83;&#x662F;&#x4E00;&#x4E2A;&#x6709;&#x72B6;&#x6001;&#x7684;widget&#xFF08;Stateful widget&#xFF09;&#x3002;&#x73B0;&#x5728;&#xFF0C;&#x6211;&#x4EEC;&#x53EF;&#x4EE5;&#x7B80;&#x5355;&#x8BA4;&#x4E3A;Stateful widget &#x548C;Stateless widget&#x6709;&#x4E24;&#x70B9;&#x4E0D;&#x540C;&#xFF1A;</p>
<ol>
<li>Stateful widget&#x53EF;&#x4EE5;&#x62E5;&#x6709;&#x72B6;&#x6001;&#xFF0C;&#x8FD9;&#x4E9B;&#x72B6;&#x6001;&#x5728;widget&#x751F;&#x547D;&#x5468;&#x671F;&#x4E2D;&#x662F;&#x53EF;&#x4EE5;&#x53D8;&#x7684;&#xFF0C;&#x800C;Stateless widget&#x662F;&#x4E0D;&#x53EF;&#x53D8;&#x7684;&#x3002;</li>
<li><p>Stateful widget&#x81F3;&#x5C11;&#x7531;&#x4E24;&#x4E2A;&#x7C7B;&#x7EC4;&#x6210;&#xFF1A;</p>
<ul>
<li>&#x4E00;&#x4E2A;<code>StatefulWidget</code>&#x7C7B;&#x3002;</li>
<li>&#x4E00;&#x4E2A; State&#x7C7B;&#xFF1B; <code>StatefulWidget</code>&#x7C7B;&#x672C;&#x8EAB;&#x662F;&#x4E0D;&#x53D8;&#x7684;&#xFF0C;&#x4F46;&#x662F; State&#x7C7B;&#x4E2D;&#x6301;&#x6709;&#x7684;&#x72B6;&#x6001;&#x5728;widget&#x751F;&#x547D;&#x5468;&#x671F;&#x4E2D;&#x53EF;&#x80FD;&#x4F1A;&#x53D1;&#x751F;&#x53D8;&#x5316;&#x3002;</li>
</ul>
<p><code>_MyHomePageState</code>&#x7C7B;&#x662F;<code>MyHomePage</code>&#x7C7B;&#x5BF9;&#x5E94;&#x7684;&#x72B6;&#x6001;&#x7C7B;&#x3002;&#x770B;&#x5230;&#x8FD9;&#x91CC;&#xFF0C;&#x7EC6;&#x5FC3;&#x7684;&#x8BFB;&#x8005;&#x53EF;&#x80FD;&#x5DF2;&#x7ECF;&#x53D1;&#x73B0;&#xFF0C;&#x548C;<code>MyApp</code> &#x7C7B;&#x4E0D;&#x540C;&#xFF0C; <code>MyHomePage</code>&#x7C7B;&#x4E2D;&#x5E76;&#x6CA1;&#x6709;<code>build</code>&#x65B9;&#x6CD5;&#xFF0C;&#x53D6;&#x800C;&#x4EE3;&#x4E4B;&#x7684;&#x662F;&#xFF0C;<code>build</code>&#x65B9;&#x6CD5;&#x88AB;&#x632A;&#x5230;&#x4E86;<code>_MyHomePageState</code>&#x65B9;&#x6CD5;&#x4E2D;&#xFF0C;&#x81F3;&#x4E8E;&#x4E3A;&#x4EC0;&#x4E48;&#x8FD9;&#x4E48;&#x505A;&#xFF0C;&#x5148;&#x7559;&#x4E2A;&#x7591;&#x95EE;&#xFF0C;&#x5728;&#x5206;&#x6790;&#x5B8C;&#x5B8C;&#x6574;&#x4EE3;&#x7801;&#x540E;&#x518D;&#x6765;&#x89E3;&#x7B54;&#x3002;</p>
</li>
</ol>
<p>   &#x63A5;&#x4E0B;&#x6765;&#xFF0C;&#x6211;&#x4EEC;&#x770B;&#x770B;<code>_MyHomePageState</code>&#x4E2D;&#x90FD;&#x5305;&#x542B;&#x54EA;&#x4E9B;&#x4E1C;&#x897F;&#xFF1A;</p>
<ol>
<li><p>&#x72B6;&#x6001;&#x3002;</p>
<pre class="language-"><code class="lang-dart">int _counter <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span>
</code></pre>
<p><code>_counter</code> &#x4E3A;&#x4FDD;&#x5B58;&#x5C4F;&#x5E55;&#x53F3;&#x4E0B;&#x89D2;&#x5E26;&#x201C;&#x2795;&#x201D;&#x53F7;&#x6309;&#x94AE;&#x70B9;&#x51FB;&#x6B21;&#x6570;&#x7684;&#x72B6;&#x6001;&#x3002;</p>
</li>
<li><p>&#x8BBE;&#x7F6E;&#x72B6;&#x6001;&#x7684;&#x81EA;&#x589E;&#x51FD;&#x6570;&#x3002;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">void</span> <span class="token function">_incrementCounter</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
     _counter<span class="token operator">++</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
</code></pre>
<p>&#x5F53;&#x6309;&#x94AE;&#x70B9;&#x51FB;&#x65F6;&#xFF0C;&#x4F1A;&#x8C03;&#x7528;&#x6B64;&#x51FD;&#x6570;&#xFF0C;&#x8BE5;&#x51FD;&#x6570;&#x7684;&#x4F5C;&#x7528;&#x662F;&#x5148;&#x81EA;&#x589E;<code>_counter</code>&#xFF0C;&#x7136;&#x540E;&#x8C03;&#x7528;<code>setState</code> &#x65B9;&#x6CD5;&#x3002;<code>setState</code>&#x65B9;&#x6CD5;&#x7684;&#x4F5C;&#x7528;&#x662F;&#x901A;&#x77E5;Flutter&#x6846;&#x67B6;&#xFF0C;&#x6709;&#x72B6;&#x6001;&#x53D1;&#x751F;&#x4E86;&#x6539;&#x53D8;&#xFF0C;Flutter&#x6846;&#x67B6;&#x6536;&#x5230;&#x901A;&#x77E5;&#x540E;&#xFF0C;&#x4F1A;&#x6267;&#x884C;<code>build</code>&#x65B9;&#x6CD5;&#x6765;&#x6839;&#x636E;&#x65B0;&#x7684;&#x72B6;&#x6001;&#x91CD;&#x65B0;&#x6784;&#x5EFA;&#x754C;&#x9762;&#xFF0C; Flutter &#x5BF9;&#x6B64;&#x65B9;&#x6CD5;&#x505A;&#x4E86;&#x4F18;&#x5316;&#xFF0C;&#x4F7F;&#x91CD;&#x65B0;&#x6267;&#x884C;&#x53D8;&#x7684;&#x5F88;&#x5FEB;&#xFF0C;&#x6240;&#x4EE5;&#x4F60;&#x53EF;&#x4EE5;&#x91CD;&#x65B0;&#x6784;&#x5EFA;&#x4EFB;&#x4F55;&#x9700;&#x8981;&#x66F4;&#x65B0;&#x7684;&#x4E1C;&#x897F;&#xFF0C;&#x800C;&#x65E0;&#x9700;&#x5206;&#x522B;&#x53BB;&#x4FEE;&#x6539;&#x5404;&#x4E2A;widget&#x3002;</p>
</li>
<li><p>&#x6784;&#x5EFA;UI&#x754C;&#x9762;</p>
<p>&#x6784;&#x5EFA;UI&#x754C;&#x9762;&#x7684;&#x903B;&#x8F91;&#x5728;<code>build</code>&#x65B9;&#x6CD5;&#x4E2D;&#xFF0C;&#x5F53;<code>MyHomePage</code>&#x7B2C;&#x4E00;&#x6B21;&#x521B;&#x5EFA;&#x65F6;&#xFF0C;<code>_MyHomePageState</code>&#x7C7B;&#x4F1A;&#x88AB;&#x521B;&#x5EFA;&#xFF0C;&#x5F53;&#x521D;&#x59CB;&#x5316;&#x5B8C;&#x6210;&#x540E;&#xFF0C;Flutter&#x6846;&#x67B6;&#x4F1A;&#x8C03;&#x7528;Widget&#x7684;<code>build</code>&#x65B9;&#x6CD5;&#x6765;&#x6784;&#x5EFA;widget&#x6811;&#xFF0C;&#x6700;&#x7EC8;&#x5C06;widget&#x6811;&#x6E32;&#x67D3;&#x5230;&#x8BBE;&#x5907;&#x5C4F;&#x5E55;&#x4E0A;&#x3002;&#x6240;&#x4EE5;&#xFF0C;&#x6211;&#x4EEC;&#x770B;&#x770B;<code>_MyHomePageState</code>&#x7684;<code>build</code>&#x65B9;&#x6CD5;&#x4E2D;&#x90FD;&#x5E72;&#x4E86;&#x4EC0;&#x4E48;&#x4E8B;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart">  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">Scaffold</span><span class="token punctuation">(</span>
      appBar<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">AppBar</span><span class="token punctuation">(</span>
        title<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Text</span><span class="token punctuation">(</span>widget<span class="token punctuation">.</span>title<span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
      body<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Center</span><span class="token punctuation">(</span>
        child<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Column</span><span class="token punctuation">(</span>
          mainAxisAlignment<span class="token punctuation">:</span> MainAxisAlignment<span class="token punctuation">.</span>center<span class="token punctuation">,</span>
          children<span class="token punctuation">:</span> <span class="token operator">&lt;</span>Widget<span class="token operator">&gt;</span><span class="token punctuation">[</span>
            <span class="token keyword">new</span> <span class="token class-name">Text</span><span class="token punctuation">(</span>
              <span class="token string">&apos;You have pushed the button this many times:&apos;</span><span class="token punctuation">,</span>
            <span class="token punctuation">)</span><span class="token punctuation">,</span>
            <span class="token keyword">new</span> <span class="token class-name">Text</span><span class="token punctuation">(</span>
              <span class="token string">&apos;$_counter&apos;</span><span class="token punctuation">,</span>
              style<span class="token punctuation">:</span> Theme<span class="token punctuation">.</span><span class="token function">of</span><span class="token punctuation">(</span>context<span class="token punctuation">)</span><span class="token punctuation">.</span>textTheme<span class="token punctuation">.</span>display1<span class="token punctuation">,</span>
            <span class="token punctuation">)</span><span class="token punctuation">,</span>
          <span class="token punctuation">]</span><span class="token punctuation">,</span>
        <span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
      floatingActionButton<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">FloatingActionButton</span><span class="token punctuation">(</span>
        onPressed<span class="token punctuation">:</span> _incrementCounter<span class="token punctuation">,</span>
        tooltip<span class="token punctuation">:</span> <span class="token string">&apos;Increment&apos;</span><span class="token punctuation">,</span>
        child<span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Icon</span><span class="token punctuation">(</span>Icons<span class="token punctuation">.</span>add<span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
</code></pre>
<ul>
<li>Scaffold &#x662F; Material&#x5E93;&#x4E2D;&#x63D0;&#x4F9B;&#x7684;&#x4E00;&#x4E2A;widget, &#x5B83;&#x63D0;&#x4F9B;&#x4E86;&#x9ED8;&#x8BA4;&#x7684;&#x5BFC;&#x822A;&#x680F;&#x3001;&#x6807;&#x9898;&#x548C;&#x5305;&#x542B;&#x4E3B;&#x5C4F;&#x5E55;widget&#x6811;&#x7684;body&#x5C5E;&#x6027;&#x3002;widget&#x6811;&#x53EF;&#x4EE5;&#x5F88;&#x590D;&#x6742;&#x3002;</li>
<li>body&#x7684;widget&#x6811;&#x4E2D;&#x5305;&#x542B;&#x4E86;&#x4E00;&#x4E2A;<code>Center</code> widget&#xFF0C;<code>Center</code> &#x53EF;&#x4EE5;&#x5C06;&#x5176;&#x5B50;widget&#x6811;&#x5BF9;&#x9F50;&#x5230;&#x5C4F;&#x5E55;&#x4E2D;&#x5FC3;&#xFF0C; <code>Center</code> &#x5B50;widget&#x662F;&#x4E00;&#x4E2A;<code>Column</code> widget&#xFF0C;<code>Column</code>&#x7684;&#x4F5C;&#x7528;&#x662F;&#x5C06;&#x5176;&#x6240;&#x6709;&#x5B50;widget&#x6CBF;&#x5C4F;&#x5E55;&#x5782;&#x76F4;&#x65B9;&#x5411;&#x4F9D;&#x6B21;&#x6392;&#x5217;&#xFF0C; &#x6B64;&#x4F8B;&#x4E2D;<code>Column</code>&#x5305;&#x542B;&#x4E24;&#x4E2A; <code>Text</code>&#x5B50;widget&#xFF0C;&#x7B2C;&#x4E00;&#x4E2A;<code>Text</code> widget&#x663E;&#x793A;&#x56FA;&#x5B9A;&#x6587;&#x672C; &#x201C;You have pushed the button this many times:&#x201D;&#xFF0C;&#x7B2C;&#x4E8C;&#x4E2A;<code>Text</code> widget&#x663E;&#x793A;<code>_counter</code>&#x72B6;&#x6001;&#x7684;&#x6570;&#x503C;&#x3002;</li>
<li>floatingActionButton&#x662F;&#x9875;&#x9762;&#x53F3;&#x4E0B;&#x89D2;&#x7684;&#x5E26;&#x201C;&#x2795;&#x201D;&#x7684;&#x60AC;&#x6D6E;&#x6309;&#x94AE;&#xFF0C;&#x5B83;&#x7684;<code>onPressed</code>&#x5C5E;&#x6027;&#x63A5;&#x53D7;&#x4E00;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#xFF0C;&#x4EE3;&#x8868;&#x5B83;&#x88AB;&#x70B9;&#x51FB;&#x540E;&#x7684;&#x5904;&#x7406;&#x5668;&#xFF0C;&#x672C;&#x4F8B;&#x4E2D;&#x76F4;&#x63A5;&#x5C06;<code>_incrementCounter</code>&#x4F5C;&#x4E3A;&#x5176;&#x5904;&#x7406;&#x51FD;&#x6570;&#x3002;</li>
</ul>
</li>
</ol>
<p>  &#x73B0;&#x5728;&#xFF0C;&#x6211;&#x4EEC;&#x5C06;&#x6574;&#x4E2A;&#x6D41;&#x7A0B;&#x4E32;&#x8D77;&#x6765;&#xFF1A;&#x5F53;&#x53F3;&#x4E0B;&#x89D2;&#x7684;floatingActionButton&#x6309;&#x94AE;&#x88AB;&#x70B9;&#x51FB;&#x4E4B;&#x540E;&#xFF0C;&#x4F1A;&#x8C03;&#x7528;<code>_incrementCounter</code>&#xFF0C;&#x5728;<code>_incrementCounter</code>&#x4E2D;&#xFF0C;&#x9996;&#x5148;&#x4F1A;&#x81EA;&#x589E;<code>_counter</code>&#x8BA1;&#x6570;&#x5668;&#xFF08;&#x72B6;&#x6001;&#xFF09;&#xFF0C;&#x7136;&#x540E;<code>setState</code>&#x4F1A;&#x901A;&#x77E5;Flutter&#x6846;&#x67B6;&#x72B6;&#x6001;&#x53D1;&#x751F;&#x53D8;&#x5316;&#xFF0C;&#x63A5;&#x7740;&#xFF0C;Flutter&#x4F1A;&#x8C03;&#x7528;<code>build</code>&#x65B9;&#x6CD5;&#x4EE5;&#x65B0;&#x7684;&#x72B6;&#x6001;&#x91CD;&#x65B0;&#x6784;&#x5EFA;UI&#xFF0C;&#x6700;&#x7EC8;&#x663E;&#x793A;&#x5728;&#x8BBE;&#x5907;&#x5C4F;&#x5E55;&#x4E0A;&#x3002;</p>
<h4 id="&#x4E3A;&#x4EC0;&#x4E48;&#x8981;&#x5C06;build&#x65B9;&#x6CD5;&#x653E;&#x5728;state&#x4E2D;&#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x653E;&#x5728;statefulwidget&#x4E2D;&#xFF1F;">&#x4E3A;&#x4EC0;&#x4E48;&#x8981;&#x5C06;build&#x65B9;&#x6CD5;&#x653E;&#x5728;State&#x4E2D;&#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x653E;&#x5728;StatefulWidget&#x4E2D;&#xFF1F;</h4>
<p>&#x73B0;&#x5728;&#xFF0C;&#x6211;&#x4EEC;&#x56DE;&#x7B54;&#x4E4B;&#x524D;&#x63D0;&#x51FA;&#x7684;&#x95EE;&#x9898;&#xFF0C;&#x4E3A;&#x4EC0;&#x4E48;<code>build()</code>&#x65B9;&#x6CD5;&#x5728;State&#xFF08;&#x800C;&#x4E0D;&#x662F;StatefulWidget&#xFF09;&#x4E2D; &#xFF1F;&#x8FD9;&#x4E3B;&#x8981;&#x662F;&#x4E3A;&#x4E86;&#x5F00;&#x53D1;&#x7684;&#x7075;&#x6D3B;&#x6027;&#x3002;&#x5982;&#x679C;&#x5C06;<code>build()</code>&#x65B9;&#x6CD5;&#x5728;StatefulWidget&#x4E2D;&#x5219;&#x4F1A;&#x6709;&#x4E24;&#x4E2A;&#x95EE;&#x9898;&#xFF1A;</p>
<ul>
<li><p>&#x72B6;&#x6001;&#x8BBF;&#x95EE;&#x4E0D;&#x4FBF;</p>
<p>&#x8BD5;&#x60F3;&#x4E00;&#x4E0B;&#xFF0C;&#x5982;&#x679C;&#x6211;&#x4EEC;&#x7684;Stateful widget &#x6709;&#x5F88;&#x591A;&#x72B6;&#x6001;&#xFF0C;&#x800C;&#x6BCF;&#x6B21;&#x72B6;&#x6001;&#x6539;&#x53D8;&#x90FD;&#x8981;&#x8C03;&#x7528;<code>build</code>&#x65B9;&#x6CD5;&#xFF0C;&#x7531;&#x4E8E;&#x72B6;&#x6001;&#x662F;&#x4FDD;&#x5B58;&#x5728;State&#x4E2D;&#x7684;&#xFF0C;&#x5982;&#x679C;&#x5C06;<code>build</code>&#x65B9;&#x6CD5;&#x653E;&#x5728;StatefulWidget&#x4E2D;&#xFF0C;&#x90A3;&#x4E48;&#x6784;&#x5EFA;&#x65F6;&#x8BFB;&#x53D6;&#x72B6;&#x6001;&#x5C06;&#x4F1A;&#x5F88;&#x4E0D;&#x65B9;&#x4FBF;&#xFF0C;&#x8BD5;&#x60F3;&#x4E00;&#x4E0B;&#xFF0C;&#x5982;&#x679C;&#x771F;&#x7684;&#x5C06;<code>build</code>&#x65B9;&#x6CD5;&#x653E;&#x5728;StatefulWidget&#x4E2D;&#x7684;&#x8BDD;&#xFF0C;&#x7531;&#x4E8E;&#x6784;&#x5EFA;&#x7528;&#x6237;&#x754C;&#x9762;&#x8FC7;&#x7A0B;&#x9700;&#x8981;&#x4F9D;&#x8D56;State&#xFF0C;&#x6240;&#x4EE5;<code>build</code>&#x65B9;&#x6CD5;&#x5C06;&#x5FC5;&#x987B;&#x52A0;&#x4E00;&#x4E2A;<code>State</code>&#x53C2;&#x6570;&#xFF0C;&#x5927;&#x6982;&#x662F;&#x4E0B;&#x9762;&#x8FD9;&#x6837;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart">  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">,</span> State state<span class="token punctuation">)</span><span class="token punctuation">{</span>
      <span class="token comment">//state.counter</span>
      <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
  <span class="token punctuation">}</span>
</code></pre>
<p>&#x8FD9;&#x6837;&#x7684;&#x8BDD;&#x5C31;&#x53EA;&#x80FD;&#x5C06;State&#x7684;&#x6240;&#x6709;&#x72B6;&#x6001;&#x58F0;&#x660E;&#x4E3A;&#x516C;&#x5F00;&#x7684;&#x72B6;&#x6001;&#xFF0C;&#x8FD9;&#x6837;&#x624D;&#x80FD;&#x5728;State&#x7C7B;&#x5916;&#x90E8;&#x8BBF;&#x95EE;&#x72B6;&#x6001;&#xFF0C;&#x4F46;&#x5C06;&#x72B6;&#x6001;&#x8BBE;&#x7F6E;&#x4E3A;&#x516C;&#x5F00;&#x540E;&#xFF0C;&#x72B6;&#x6001;&#x5C06;&#x4E0D;&#x518D;&#x5177;&#x6709;&#x79C1;&#x5BC6;&#x6027;&#xFF0C;&#x8FD9;&#x6837;&#x4F9D;&#x8D56;&#xFF0C;&#x5BF9;&#x72B6;&#x6001;&#x7684;&#x4FEE;&#x6539;&#x5C06;&#x4F1A;&#x53D8;&#x7684;&#x4E0D;&#x53EF;&#x63A7;&#x3002;&#x5C06;<code>build()</code>&#x65B9;&#x6CD5;&#x653E;&#x5728;State&#x4E2D;&#x7684;&#x8BDD;&#xFF0C;&#x6784;&#x5EFA;&#x8FC7;&#x7A0B;&#x5219;&#x53EF;&#x4EE5;&#x76F4;&#x63A5;&#x8BBF;&#x95EE;&#x72B6;&#x6001;&#xFF0C;&#x8FD9;&#x6837;&#x4F1A;&#x5F88;&#x65B9;&#x4FBF;&#x3002;</p>
</li>
<li><p>&#x7EE7;&#x627F;StatefulWidget&#x4E0D;&#x4FBF;</p>
<p>&#x4F8B;&#x5982;&#xFF0C;Flutter&#x4E2D;&#x6709;&#x4E00;&#x4E2A;&#x52A8;&#x753B;widget&#x7684;&#x57FA;&#x7C7B;<code>AnimatedWidget</code>&#xFF0C;&#x5B83;&#x7EE7;&#x627F;&#x81EA;<code>StatefulWidget</code>&#x7C7B;&#x3002;<code>AnimatedWidget</code>&#x4E2D;&#x5F15;&#x5165;&#x4E86;&#x4E00;&#x4E2A;&#x62BD;&#x8C61;&#x65B9;&#x6CD5;<code>build(BuildContext context)</code>&#xFF0C;&#x7EE7;&#x627F;&#x81EA;<code>AnimatedWidget</code>&#x7684;&#x52A8;&#x753B;widget&#x90FD;&#x8981;&#x5B9E;&#x73B0;&#x8FD9;&#x4E2A;<code>build</code>&#x65B9;&#x6CD5;&#x3002;&#x73B0;&#x5728;&#x8BBE;&#x60F3;&#x4E00;&#x4E0B;&#xFF0C;&#x5982;&#x679C;<code>StatefulWidget</code> &#x7C7B;&#x4E2D;&#x5DF2;&#x7ECF;&#x6709;&#x4E86;&#x4E00;&#x4E2A;<code>build</code>&#x65B9;&#x6CD5;&#xFF0C;&#x6B63;&#x5982;&#x4E0A;&#x9762;&#x6240;&#x8FF0;&#xFF0C;&#x6B64;&#x65F6;<code>build</code>&#x65B9;&#x6CD5;&#x9700;&#x8981;&#x63A5;&#x6536;&#x4E00;&#x4E2A;state&#x5BF9;&#x8C61;&#xFF0C;&#x8FD9;&#x5C31;&#x610F;&#x5473;&#x7740;<code>AnimatedWidget</code>&#x5FC5;&#x987B;&#x5C06;&#x81EA;&#x5DF1;&#x7684;State&#x5BF9;&#x8C61;(&#x8BB0;&#x4E3A;_animatedWidgetState)&#x63D0;&#x4F9B;&#x7ED9;&#x5176;&#x5B50;&#x7C7B;&#xFF0C;&#x56E0;&#x4E3A;&#x5B50;&#x7C7B;&#x9700;&#x8981;&#x5728;&#x5176;<code>build</code>&#x65B9;&#x6CD5;&#x4E2D;&#x8C03;&#x7528;&#x7236;&#x7C7B;&#x7684;<code>build</code>&#x65B9;&#x6CD5;&#xFF0C;&#x4EE3;&#x7801;&#x53EF;&#x80FD;&#x5982;&#x4E0B;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">class</span> <span class="token class-name">MyAnimationWidget</span> <span class="token keyword">extends</span> <span class="token class-name">AnimatedWidget</span><span class="token punctuation">{</span>
    <span class="token metadata symbol">@override</span>
    Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">,</span> State state<span class="token punctuation">)</span><span class="token punctuation">{</span>
      <span class="token comment">//&#x7531;&#x4E8E;&#x5B50;&#x7C7B;&#x8981;&#x7528;&#x5230;AnimatedWidget&#x7684;&#x72B6;&#x6001;&#x5BF9;&#x8C61;_animatedWidgetState&#xFF0C;</span>
      <span class="token comment">//&#x6240;&#x4EE5;AnimatedWidget&#x5FC5;&#x987B;&#x901A;&#x8FC7;&#x67D0;&#x79CD;&#x65B9;&#x5F0F;&#x5C06;&#x5176;&#x72B6;&#x6001;&#x5BF9;&#x8C61;_animatedWidgetState</span>
      <span class="token comment">//&#x66B4;&#x9732;&#x7ED9;&#x5176;&#x5B50;&#x7C7B;   </span>
      <span class="token keyword">super</span><span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span>context<span class="token punctuation">,</span> _animatedWidgetState<span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<p>&#x8FD9;&#x6837;&#x5F88;&#x663E;&#x7136;&#x662F;&#x4E0D;&#x5408;&#x7406;&#x7684;&#xFF0C;&#x56E0;&#x4E3A;</p>
<ol>
<li><code>AnimatedWidget</code>&#x7684;&#x72B6;&#x6001;&#x5BF9;&#x8C61;&#x662F;<code>AnimatedWidget</code>&#x5185;&#x90E8;&#x5B9E;&#x73B0;&#x7EC6;&#x8282;&#xFF0C;&#x4E0D;&#x5E94;&#x8BE5;&#x66B4;&#x9732;&#x7ED9;&#x5916;&#x90E8;&#x3002;</li>
<li>&#x5982;&#x679C;&#x8981;&#x5C06;&#x7236;&#x7C7B;&#x72B6;&#x6001;&#x66B4;&#x9732;&#x7ED9;&#x5B50;&#x7C7B;&#xFF0C;&#x90A3;&#x4E48;&#x5FC5;&#x987B;&#x5F97;&#x6709;&#x4E00;&#x79CD;&#x4F20;&#x9012;&#x673A;&#x5236;&#xFF0C;&#x800C;&#x505A;&#x8FD9;&#x4E00;&#x5957;&#x4F20;&#x9012;&#x673A;&#x5236;&#x662F;&#x65E0;&#x610F;&#x4E49;&#x7684;&#xFF0C;&#x56E0;&#x4E3A;&#x7236;&#x5B50;&#x7C7B;&#x4E4B;&#x95F4;&#x72B6;&#x6001;&#x7684;&#x4F20;&#x9012;&#x548C;&#x5B50;&#x7C7B;&#x672C;&#x8EAB;&#x903B;&#x8F91;&#x662F;&#x65E0;&#x5173;&#x7684;&#x3002;</li>
</ol>
</li>
</ul>
<p>&#x7EFC;&#x4E0A;&#x6240;&#x8FF0;&#xFF0C;&#x53EF;&#x4EE5;&#x53D1;&#x73B0;&#xFF0C;&#x5BF9;&#x4E8E;StatefulWidget&#xFF0C;&#x5C06;<code>build</code>&#x65B9;&#x6CD5;&#x653E;&#x5728;State&#x4E2D;&#xFF0C;&#x53EF;&#x4EE5;&#x7ED9;&#x5F00;&#x53D1;&#x5E26;&#x6765;&#x5F88;&#x5927;&#x7684;&#x7075;&#x6D3B;&#x6027;&#x3002;</p>

                                
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